It's all speculation and I assume no details of Peter's personal dealings with WSP will ever publically be released, but there's plenty of explanations you could conjure up that are along the lines of him looking after himself and completely shafting current shareholders (fortunately I'm not one of them).His actions on leaving seem reasonable to me.
I'm pretty sure the break-up value of HHL itself would be more than $1 per share.
Key personnel with concentrated interests in publically listed companies - there's a big grey area in what they should be doing in terms of the interests of all shareholders and what is best for their personal wealth IMO.